Sex hormones, such as estrogens, are believed to play a major role in gender-based differential immune competence and autoimmunity. One mechanism by which estrogens may influence the immune system is by regulating cytokine levels. We have recently reported that estrogen-treated wild type C57BL/6 mice have increased IFNy mRNA and protein levels. This grant proposal is aimed at mechanistically studying how estrogen alters the production of lFNy and the molecular consequences of increased IFNz Estrogen-induced IFN'/is significant, since IFNy is a "master" cytokine with physiological effects on nearly all ceils of the immune system: it is involved in resistance against intracellular infections, and in pathological effects of many autoimmune and inflammatory diseases. The hypothesis of this proposal is that increased IFNy in estrogen-treated mice is due to the promotion of increased numbers of specific IFNy secreting cells, an enhanced response to IFN[unreadable] -promoting cytokines and/or eo-stimulatory signals. A consequence of this increased IFNy will be altered cellular and molecular functions of IFN[unreadable] target cells. This may be evident as increased expression of IFNy responsive genes and molecules, altered patterns of apoptosis and changes in susceptibility to autoimmunity. _ of this proposal will examine the molecular basis for estrogen-induced IFNy. _ will determine whether responsiveness of IFNy-target ceils to IFNy is altered in estrogen-treated mice, with regard to STAT1 activation, IFNy-responsive genes, and expression of IRF-1, IRF-2, Cox-2, and MHC molecules. _ will investigate whether increased survival oflymphocvtes from estrogen-treated mice is due to IFNy inducible nitric oxide, by using estrogen-treated wild type, IFNy knockout, and iNOS knockout mice. _1 will address whether estrogen treated non-autoimmune mice are prone to develop selected types ofinduced-autoimmuni_ and whether this is due to IFNy. This proposal is novel since it will provide a mechanistic-based understanding of how estrogen promotes IFNy and its consequences at molecular, cellular and organismal levels. The proposal will benefit the future understanding of human health, especially with regard to gender-based immune diseases. PERFORMANCESITE(S) (organizationc, ity,state) Center for Molecular Medicine and Infectious Diseases (CMMID) Dept. of Biomedical Sciences and Pathobiology Virginia-Maryland Regional College of Vet. Med. Virginia Tech University 1410, Prices Fork Road, Blacksburg, VA 24061 KEYPERSONNEL.See instructions. Usecontinuationpagesas neededto providetherequiredinformationin theformat shownbelow. StartwithPrincipaIlnvestigator.Listallotherkeypersonnelinalphabeticaolrder,lastnamefirst. Name Organization Role onProject Ahrned, Ansaf Virginia Tech Principal Investigator Christadcss, P. Univ. Texas Med. Branch Co-Investigator Elvinger, F. Virginia Tech Co-Investigator Huckle, W.R. Virginia Tech Co-Investigator Ju, Shyr-Te Boston University Co-Investigator King, C. Virginia Tech Postdoctoral Fellow Kruzelock, R. Virginia Tech Co-Investigator Lengi, A. Virginia Tech Lab Specialist Saunders, G. Virginia Tech Co-Investigator DisclosurePermissionStatement.APPlicableto SBIR/STTROnly. See instructions[]. Yes [] No + PHS398(Rev.05101) Page_2 FormPage2 * ! Principal Investigator/Program Director (Last, first, middle): Ahrned. Ansar The name of the principal investigator/program director must be provided at the top of each printed page and each continuation page. RESEARCH GRANT TABLE OF CONTENTS Page Numbers Face Page ......................................................................................................................................................... 1 Description,